relation.h

/*-------------------------------------------------------------------------
 *
 * relation.h--
 *	  Definitions for internal planner nodes.
 *
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 * $Id: relation.h,v 1.5 1997/09/07 04:58:48 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#ifndef RELATION_H
#define RELATION_H

#include <nodes/parsenodes.h>
#include <nodes/primnodes.h>

/*
 * Relid
 *		List of relation identifiers (indexes into the rangetable).
 */

typedef List   *Relid;

/*
 * Rel
 *		Per-base-relation information
 *
 *		Parts of this data structure are specific to various scan and join
 *		mechanisms.  It didn't seem worth creating new node types for them.
 *
 *		relids - List of relation indentifiers
 *		indexed - true if the relation has secondary indices
 *		pages - number of pages in the relation
 *		tuples - number of tuples in the relation
 *		size - number of tuples in the relation after restrictions clauses
 *			   have been applied
 *		width - number of bytes per tuple in the relation after the
 *				appropriate projections have been done
 *		targetlist - List of TargetList nodes
 *		pathlist - List of Path nodes, one for each possible method of
 *				   generating the relation
 *		unorderedpath - a Path node generating this relation whose resulting
 *						tuples are unordered (this isn't necessarily a
 *						sequential scan path, e.g., scanning with a hash index
 *						leaves the tuples unordered)
 *		cheapestpath -	least expensive Path (regardless of final order)
 *		pruneable - flag to let the planner know whether it can prune the plan
 *					space of this Rel or not.  -- JMH, 11/11/92
 *
 *	 * If the relation is a (secondary) index it will have the following
 *		three fields:
 *
 *		classlist - List of PG_AMOPCLASS OIDs for the index
 *		indexkeys - List of base-relation attribute numbers that are index keys
 *		ordering - List of PG_OPERATOR OIDs which order the indexscan result
 *		relam	  - the OID of the pg_am of the index
 *
 *	 * The presence of the remaining fields depends on the restrictions
 *		and joins which the relation participates in:
 *
 *		clauseinfo - List of ClauseInfo nodes, containing info about each
 *					 qualification clause in which this relation participates
 *		joininfo  - List of JoinInfo nodes, containing info about each join
 *					clause in which this relation participates
 *		innerjoin - List of Path nodes that represent indices that may be used
 *					as inner paths of nestloop joins
 *
 * NB. the last element of the arrays classlist, indexkeys and ordering
 *	   is always 0.								2/95 - ay
 */

typedef struct Rel
{
	NodeTag			type;

	/* all relations: */
	Relid			relids;

	/* catalog statistics information */
	bool			indexed;
	int				pages;
	int				tuples;
	int				size;
	int				width;

	/* materialization information */
	List		   *targetlist;
	List		   *pathlist;
	struct Path    *unorderedpath;
	struct Path    *cheapestpath;
	bool			pruneable;

	/* used solely by indices: */
	Oid			   *classlist;	/* classes of AM operators */
	int			   *indexkeys;	/* keys over which we're indexing */
	Oid				relam;		/* OID of the access method (in pg_am) */

	Oid				indproc;
	List		   *indpred;

	/* used by various scans and joins: */
	Oid			   *ordering;	/* OID of operators in sort order */
	List		   *clauseinfo; /* restriction clauses */
	List		   *joininfo;	/* join clauses */
	List		   *innerjoin;
	List		   *superrels;
}				Rel;

extern Var	   *get_expr(TargetEntry * foo);

typedef struct MergeOrder
{
	NodeTag			type;
	Oid				join_operator;
	Oid				left_operator;
	Oid				right_operator;
	Oid				left_type;
	Oid				right_type;
}				MergeOrder;

typedef enum OrderType
{
	MERGE_ORDER, SORTOP_ORDER
}				OrderType;

typedef struct PathOrder
{
	OrderType		ordtype;
	union
	{
		Oid			   *sortop;
		MergeOrder	   *merge;
	}				ord;
}				PathOrder;

typedef struct Path
{
	NodeTag			type;

	Rel			   *parent;
	Cost			path_cost;

	NodeTag			pathtype;

	PathOrder		p_ordering;

	List		   *keys;
	Cost			outerjoincost;
	Relid			joinid;
	List		   *locclauseinfo;
}				Path;

typedef struct IndexPath
{
	Path			path;
	List		   *indexid;
	List		   *indexqual;
	int			   *indexkeys;	/* to transform heap attnos into index
								 * ones */
}				IndexPath;

typedef struct JoinPath
{
	Path			path;
	List		   *pathclauseinfo;
	Path		   *outerjoinpath;
	Path		   *innerjoinpath;
}				JoinPath;

typedef struct MergePath
{
	JoinPath		jpath;
	List		   *path_mergeclauses;
	List		   *outersortkeys;
	List		   *innersortkeys;
}				MergePath;

typedef struct HashPath
{
	JoinPath		jpath;
	List		   *path_hashclauses;
	List		   *outerhashkeys;
	List		   *innerhashkeys;
}				HashPath;

/******
 * Keys
 ******/

typedef struct OrderKey
{
	NodeTag			type;
	int				attribute_number;
	Index			array_index;
}				OrderKey;

typedef struct JoinKey
{
	NodeTag			type;
	Var			   *outer;
	Var			   *inner;
}				JoinKey;

/*******
 * clause info
 *******/

typedef struct CInfo
{
	NodeTag			type;
	Expr		   *clause;		/* should be an OP clause */
	Cost			selectivity;
	bool			notclause;
	List		   *indexids;

	/* mergesort only */
	MergeOrder	   *mergesortorder;

	/* hashjoin only */
	Oid				hashjoinoperator;
	Relid			cinfojoinid;
}				CInfo;

typedef struct JoinMethod
{
	NodeTag			type;
	List		   *jmkeys;
	List		   *clauses;
}				JoinMethod;

typedef struct HInfo
{
	JoinMethod		jmethod;
	Oid				hashop;
}				HInfo;

typedef struct MInfo
{
	JoinMethod		jmethod;
	MergeOrder	   *m_ordering;
}				MInfo;

typedef struct JInfo
{
	NodeTag			type;
	List		   *otherrels;
	List		   *jinfoclauseinfo;
	bool			mergesortable;
	bool			hashjoinable;
	bool			inactive;
}				JInfo;

typedef struct Iter
{
	NodeTag			type;
	Node		   *iterexpr;
	Oid				itertype;	/* type of the iter expr (use for type
								 * checking) */
}				Iter;

/*
** Stream:
**	 A stream represents a root-to-leaf path in a plan tree (i.e. a tree of
** JoinPaths and Paths).  The stream includes pointers to all Path nodes,
** as well as to any clauses that reside above Path nodes.	This structure
** is used to make Path nodes and clauses look similar, so that Predicate
** Migration can run.
**
**	   pathptr -- pointer to the current path node
**		 cinfo -- if NULL, this stream node referes to the path node.
**				  Otherwise this is a pointer to the current clause.
**	clausetype -- whether cinfo is in locclauseinfo or pathclauseinfo in the
**				  path node
**	  upstream -- linked list pointer upwards
**	downstream -- ditto, downwards
**	   groupup -- whether or not this node is in a group with the node upstream
**	 groupcost -- total cost of the group that node is in
**	  groupsel -- total selectivity of the group that node is in
*/
typedef struct Stream *StreamPtr;

typedef struct Stream
{
	NodeTag			type;
	Path		   *pathptr;
	CInfo		   *cinfo;
	int			   *clausetype;
	struct Stream  *upstream;
	struct Stream  *downstream;
	bool			groupup;
	Cost			groupcost;
	Cost			groupsel;
}				Stream;

#endif							/* RELATION_H */